Hello, I have been unable to finish my MCP model because I cant find the way to add a constraint that is an equality. When I try combining and adding that constraint as @constraint or @NLconstraint and the others with @mapping, it does not work.

but you might need to be a bit careful, depending on the formulation of rest of your model. (In the model above, there’s effectively a hidden constraint that @constraint(model, 0 * x ⟂ x).)